Transformer



' .1. M. WILSGN TRANSFOBMER Filed Aprii 24, 1941 Marek 7, 1944.

IINVENTOR -Johm 'M'.Wlomd BY A l ATTORNEY that it may be held out Patented Mar. 7, 1944 TRANSFORMER John M. Wilson, Minneapolis, Minn., assignor to Minneapolis-Honeywell lRegulator Company, Minneapolis, Minn., a corporation of Delaware Application April 24, 1941, Serial No.-390,098

12 Claims.

This invention relates to transformers in general, and one of its objects is to vprovide .a construction which shall be more compact and keasier to assemble than those of the prior art.

Another object of the present invention is to i construct an improved transformer having a high voltage secondary winding, and insulators for high voltage leads projecting through said housing. A further object is to provide, in such a transformer, improved means for supporting the core, windings, and insulators within the housing.

A further object of the invention is to provide a transformer structure whereby the core, windings and insulators for high voltage leads may be assembled as a unit and housing. A still further object is to construct such a core, winding, and insulator unit which will not obstruct the flow of a thermoplastic insulating material into the housing after the unit is p-laced therein.

A further object of the` invention is to provide, in a transformer having a high voltage secondary winding and means for shielding .said secondary winding, a structure whereby the shielding means, core and windings maybe assembled as a unit.

A further object of the invention is to provide ,a transformer core structure made up of two stacks of laminations, so constructed that one winding may be assembled with one stack, and the other winding with theother stack, and the two stacks may then be assembled by the cooperation of notches on the laminations. A still further object is to provide a shielding structure for one of said windings which may be assembled simultaneously with the core and windings.

A further object is to provide a mounting bracket for a core, Winding and shield assembly of the type described which may be readily attaohed to the complete assembly. A still further object is to provide such a bracket which is adapted to support insulators for carrying high voltage leads through the transformer housing.

A further object of the invention is to provide a shield structure for a transformer wind-ing which is of flexible material, and so constructed vof its effective shielding position while the transformer housing is being filled with sealing material, and thereafter `bent so as to take on its shielding position.

Another object of the invention is to construct a transformer casing including means for mounting auxiliary electrical equipment on one side thereof, and to provide therein improved means l for shielding one of the windings from the other then placed within a winding .and from said auxiliary electrical equipment.

A further object .of .the present invention is to provide improved methods ofassembling transformer structures land to construct a transformer which is readily adapted to such assembly methods.

Other objects and `advantages .of my invention will .become apparent from-a considerationof the attached specification, claims, and drawing, in .which Figure l yrepresents a vertical .cross section through a transformer embodying my invention,

Figure 2 represents Ia horizontal section taken on Athe line 2--2 .of Figure 1, looking in the direction of the arrows,

Figure 3 rrepresents an elevation of the internal assembly unit of vthedevice shown in Figures l and 2, looking from the right in Figure 2.

Figures 4 and 5 are sketches on a smaller scale, showing details of the core and winding construction used in vmy invention, and indicating certain assembly methods, and

Figure 6 is a view of the shielding means employed in the device shown in the other figures, on a smaller scale.

Figu-re 7 is a fragmentary view of the supporting bracket used in my invention and illustrates the m-anner in .which an insulator member is secured thereto.

The `drawing discloses a transformer device mounted on a base .plate I0, which is provided with any suitable means, such as the slots I I, to facilitate mounting of the device on a supporting structure. Attached to the base plate I0 in any desired manner is a housing member I2, shaped vgenerally like a box with two adjacent sides left open. One of these open sides is closed by the base plate I0, and the other, which happens to be the lower side as the device appears in VFigure l, is closed by a partition member I3 having upturned edges which are fastened to the housing member I2 by any suitable means, such as the bolts I4.

Mounted in the space enclosedby base plate I0, housing member I2, and partition kmember I3 is a transformer assembly unit generally indicated at I5 and shown separately in Figure 3. This unit I5 is fastened to the sides of housing member I2 by screws I6.

Mounted on lthe under side of the `partition vmember I3, as it vappears in the drawing, is a relay generally "indicated at 20 and a switch mechanism generally indicated at 2I. The -particular auxiliary electrical apparatus mounted on vthe plate I3 forms no part of the present invention. This auxiliary electrical apparatus is enclosed by a housing member 22 which is complementary with the housing member I2. The housing member 22 is held in place by the cooperation of a threaded post 23, mounted on the partition member I3 by any suitable means, and an internally threaded coupling member 24. The coupling member 24 extends through the housing member 22. The part of the coupling member outside the housing is provided with a. shoulder to engage the housing and a knurled portion to permit the coupling member to be manually threaded on said post.

The internal assembly unit I comprises a bracket member generally indicated at 3U, having a base portion 3I, side flanges32, and an end ange 33. The base portion 3l extends vertically in Figures 2 and 3, and is ybest shown in Figure 2, being generally in the shape of a hollow square. The side flanges 32, appearing in Figures 1 and 3, are turned at right angles to the base portion 3I, and are provided with internally threaded holes 34 which cooperate with the screws I6 to hold the assembly unit I5 in the casing member I2. The end flange 33, shown in Figures 2 and 3, is also turned at right angles to the base portion 3 I, but in a direction opposite to the side flanges 32. This end flange is provided with suitable apertures for receiving high voltage insulator members 35. When the bracket 30 is rst made, the apertures for receiving the insulator members 35 are Wider than they now appear in the drawing, in order that the Wide lower portions of the insulator 35 may be passed through the apertures. After the wide portions of the insulators 35 have been passed through these apertures, a suitable tool is inserted through each of two smaller apertures 36 provided at each side of the larger aperture, and by a suitable twisting motion the tool is made to deform the material of the bracket so that it engages the sides of the insulators 35.

Mounted on the base portion 3I of the bracket 30 by any conventional means such as the bolts indicated at 40, is a core structure generally indicated at 4I, on which are supported a primary winding 42, secondary windings 43, and a shielding member 44.

The core structure 4I is made up oi laminations of suitable magnetic material. Each layer of laminations consists of two complementary generally F-shaped pieces 5I] and 5I shownA in detail in Figures 4 and 5, respectively. When stacked and assembled these laminations form a central winding leg 52, a pair of side legs 53 and a pair of end yoke members 54 connecting all three of said legs. These leg and yoke members taken together complete the core structure 4I of the transformer.

Each lamination 50 is of a generally F-shaped cross-section and comprises a pair of cross-bars 6l) and 6I connected by a .portion 62 which may be regarded as the upright member of the F. On the left-hand side of the cross-bars 60 and BI, as they appear in Figure 4, are projections 63.

VNotches 64 are provided in the ends of the members 60 and 62, and holes 65 are provided in the laminations 5U in order to permit the passage of the bolts 40 therethrough.

The 1aminations 5I are similar in shape to the laminations 50. Cross-bars 10 and 1I are provided, and the F-shape is completed by an upright member 12. Projections 13 are located on the right-hand side of cross-bars 10 and 1I, as

they appear in Figure 5. Notches 14 are located at the ends of members 13 and 12, and holes 15 are provided for the passage of bolts 43 through the laminations.

The only difference between the laminations 5U and the laminations 5I lies in the distance between the upright B2 and the projections 63, as contrasted with the distance between upright 12 and projections 13. This difference is necessary because of the different amounts of space taken up by the windings 42 and 43. If both windings iilled an equal amount of space, the laminations 50 and 5I might be identical.

When the core structure is assembled, the projections 63 and 'I3 cooperate to form a magnetic shunt between the primary winding 42 and the secondary windings 43.

The windings 43 are high voltage windings, and suitable insulating members 45 and 46 are provided to insulate these windings from each other and from the core structure 4I. The insulating members 45, which extend horizontally in Figures 2 and 4, are `provided with apertures to permit the passage of the central winding legs 52 of the :core structure therethrough.

The shielding member 44 is composed of some flexible, electrically conductive material, such as sheet copper for example, and comprises a portion extending transversely to the core structure 4I and a portion 8| extending parallel to the core structure 4I. The portion 80 is provided with a central opening 82 to accommodate the central winding leg 52 of the core structure. Openings 83 are also provided at the sides of the portion 80 to accommodate the side legs 53 of the core structure. A narrow slit 84 is out through the portion 80 from the central opening 82 to its outside edge, in order that a circulating curent may not be induced in the shield 44 by the magnetic field in the core structure.

Method of assembly The first step in assembling a transformer such as that disclosed herein is the building of the core and Winding structure. A suitable number of laminations 50 are piled together to form a stack. Then the following parts are slipped over the cross-bars 6I of the laminations in the stack: an insulating member 45, a Winding 43, another insulating member 45, another winding 43, and another insulating member 45, and the shielding member44. These parts are moved to the position shown in dotted lines in Figure 4.

A similar stack of laminations 5I is prepared. A winding 42 is slipped over the cross-bars 5I of the stacked laminations 52, and moved to the position shown in dotted lines in Figure 5.

The two stacks of laminations; with the coils assembled thereon, are then moved together so that the cross-bars BI and 1I compliment each other to form the central winding leg 52. When the stacks are nearly in complete engagement it is `necessary to apply considerable force to cause the projections adjacent the notches B4 and 14 to slip over the opposite projections and engage the notches. After the projections have snapped into engagement with the notches 64 and 14, the entire core and winding unit is permanently assembled and cannot be readily disengaged.

The projecting wing portions 85 of the transverse portion B0 of the shield member 44 are then bent along the line 8S to a position which would be vertical as viewed in Figure 2. After this is done the bracket 30 may be moved into engagement with the core structure 4I, without interfering with the shield 44. After the bracket 3U is moved into engagement with the core struc- 'ture 4I, it is fastened thereto by means of the bolts 40. The portions 85 of the shieldV member 44 are then bent back to their original position, indicated in Figure 2.

The insulating members 46 place at this time.

The-insulating members 35 are then inserted in the openings in the end flange 33 of the bracket .30, in -the manner previously described. The leads vfrom the windings 43 are attached in any desirable manner to the connectors which extend through the insulators 35, and the entire internal transformer assembly unit I5 .is then ready for insertion in the casing.

The assembly unit I5 is then placed in the housing ymember I2, and fastened therein by means of the screws I6 cooperating with the threaded may be slipped into ,holes 34 in kthe bracket member 3U. The .base

member I 0, in which holes are provided to re,- ceive the insulators 35, is then placed over one open side of the housing memberV I2 so that the insulators 35 project through the holes as shown in Figure 2. The base plate I0 may be fastened to the casing member I2 by any suitable means (not shown).

The entire structure which has been assembled -so far is then placed in a position upside down from that shown in Figure 1, so that it forms a cup-shaped housing with the transformer inside. At this time, the shield 44 has not yet been bent at right Iangles along the line 8l, so that the portion BI of the shield member AI4 extends transversely to the core structure 4I, or in a vertical direction. The cup-shaped housing containing the transformer is then iilled with a suitable ther- .moplastic insulating material which has been heated to its iiuid state. After al1 the windings .have been covered by this material the shield member 44 is bent along the line 31 so that the portion 8l extends parallel to the core structure 4I and its edges substantially engage the edges 0f the housing. The partition member I3 with the auxiliary equipment mounted thereon is then placed over the open side of the casing member I2 and fastened in place by the bolts I4.

The casing member 22 may then be fastened over this auxiliary equipment bythe mechanism previously described, and the assembly is then complete.

It will be seen that I have provided a transformer structure which is extremely compact and whichis capable of rapid assembly. It should be .further noted that the device is so constructed that spaces are left between the windings and the'side legs to permit free now of thermoplastic insulating material therebetween, so that the windings may be completely insulated after assembly.

Since other modifications of my invention will readily occur to those skilled in the art, my invention is not to be construed as limited by the present disclosure, but only by the appended claims.

I claim as my invention:

l. A transformer, comprising in combination, a housing for said transformer having apertures therein, a core and winding mounted on said core, leads connected to said windings and extending through said housing, means for insulating the leads associated with at least one of said windings from said housing, a unitary bracket, means for securing said insulating means thereto, means for assembling said core, windings insulating means and bracket as a unit,

said unit being insertable in said housing, said bracket serving to support said unit in said housing and means for attachingv said bracket to said housing in a position whereby Asaid insulating means extends through said apertures.

' `2. A transformer, comprising in combination, a housing for said transformer having apertures therein, a core and at least two twindings on said core, shielding means mounted on said core between said windings, conductors extending yfrom said windings through said housing, means for insulating the conductors associated with at vleast one of .said windings from said housing, a bracket, means for securing said insulating means thereto, means for assembling said core, windings, shielding means, insulating means and bracket as a unit, .said unit being insertable in said housing, said lbracket serving to support said unit in said housing, and means for .attaching said bracket to .said housing in a position whereby said insulating means extends through said apertures.

3. A transformer, comprising in combination, a housing for said transformer, means for mounting auxiliary electrical equipment on one `side of said housing, a core and at least two windings on said core, shielding means mounted :on said core between said windings so as to `shield one winding from the other, said shielding means having a portion extending between said one winding and said one side of the housing so as to shield said one winding from said auxiliary equipment, conductors extending from said windings through said housing, means for insulating the conductors associated with at least one of said Awindings from said housing, a bracket for supporting said core, windings, shielding means, and insulating means, means for assembling said core, windings, shielding means, insulating means and bracket as a unit, said unit being insertable in said housing, and means for attaching said bracket to said housing.

f4. A transformer core construction, comprising a plurality of stacked laminations, forming a central Winding leg, a pair of side legs spaced therefrom and parallel thereto, a pair of yoke portions joining all said legs at their ends, and magnetic shunt portions extending between said winding leg and said side legs, each layer of said laminations comprising two similar, generally F- shaped pieces positioned inversely with respect to each other, lthe upright portion of each F-shaped piece forming one of said yoke portions, the upper cross-bar of each F-shaped piece forming one of said side legs, and the central cross-bars of said F-shaped pieces cooperating to form said winding leg, said shunt portion comprising a projection depended from each of said cross-bars, said projections on the two pieces extending toward but not engaging each other when the core is assembled.

5. A transformer core construction, comprising in combination, two stacks of generally F- shaped laminations, each lamination having a projection depending from each cross-bar of said F, and notches on at least two of the extremities of said F, said stacks being adapted for assembly with said F-shapes inverted with respect to each other, and their ends in contact, said projections cooperating to form a magnetic shunt for said core, the central cross-bars of said F-shapes engaging each other so that said assembled stacks may not be separated in a lateral direction, and said notches engaging each other so that said assembled stacks may not be separated in a longitudinal direction.

6. A transformer, comprising in combination, a pair of windings of annular cross-section, a core structure including two stacks of generally F-shaped laminations, each lamination having a projection depending from each cross-bar of said F, and notches on at least two of the extremities of said F, said stacks being adapted for assembly with said F-shapes inverted with respect to each other, and their ends in contact, said projections cooperating to form a magnetic shunt for said core, said notches engaging each other so that said assembled stacks may not be separated, said windings being of suiliciently large internal diameter to be receivable on the central cross- ,bar of one of said stacks over the projection thereon, said central cross-bars of said two stacks serving when assembled as complementary portions of a winding leg for said core structure, and said projections serving to hold said windings in place on said leg.

7. A transformer, comprising in combination, a housing for said transformer, means for mounting auxiliary electrical equipment on one side of said housing, a core and at least two windings on said core, shielding means mounted on said core between said windings so as to shield one windings from the other, said shielding means having a portion extending between said one winding and said one side of the housing so as to shield said one winding from said auxiliary equipment.

8. A transformer, comprising in combination, a core structure, at least two windings mounted on said core structure, flexible shielding means mounted on said core between said windings and a housing for said transformer comprising a metallic main portion to which said core is xed, and a removable cover portion, said core structure extending substantially parallel to said cover, said shielding means comprising a portion extending transversely to said core structure and a portion extending substantially parallel to said cover portion between one of said windings and said cover portion, said main portion and said shielding means cooperating to shield said one winding completely, said one Winding being accessible upon removal of said cover and bending back of the parallel portion of said iiexible shielding means.

9. A transformer, comprising in combination, a pair of windings of annular cross-section,

shielding means having an opening therein shaped similarly to the openings in said windings, a core structure including two stacks of generally F-shaped laminations, each, lamination having a projection depending from each crossbar of said F, and notches on at least two of the extremities of said F, said stacks being adapted for assembly with said F-shapes inverted with respect to each other, and their ends in contact, said projections cooperating to form a magnetic shunt for said core` said notches engaging each other so that said assembled stacks may not be .separated in a longitudinal direction, said openings being of sufficiently large internal diameter to be receivable on the central cross-bar of one of said stacks over the projection thereon, said central cross-bars of said two stacks serving when assembled as complementary portions of a winding leg for said core structure, and said projections serving to hold said windings and said shielding means in place on said leg.

l0. A transformer, comprising in combination, a core and windings mounted on said core, an apertured housing for enclosing said core and windings, a bracket mounted within said housing, means for securing said core to said bracket, leads connected to said windings and supported by said bracket, means for insulating each lead from said bracket comprising a hollow insulator having a terminal therein, said lead being connected to said terminal, and means for securing said insulator to said bracket comprising an aperture in said bracket for receiving said insulator and aligned with a corresponding aperture in said housing adapted to receive said insulator, said insulator having an annular recess adjacent said aperture, a plurality of apertures in said bracket adjacent said first aperture deiining small portions of said bracket adjacent said recess, and said small portions being bendable toward said insulator to enter said recess thereby securing said insulator to said bracket.

1l. In a transformer, in combination, a core having at least two windings mounted on said core, said core comprising a frame, iiexible shielding means mounted on said core between said windings and extending transversely to said core, and a bracket for supporting said windings and core, said bracket having an opening corresponding to the opening of said core frame, and said flexible shielding means having ear means projecting outwardly beyond the boundary of said frame opening so as to extend completely between said windings, said ear means being bendable so as to permit said shield to extend through r the opening in said bracket to permit attach- .rent of the bracket to the core, and bendable back to the original position thereof after attachment of said bracket to said core.

12. A transformer core construction, comprising in combination, two stacks of generally F- shaped laminations, each lamination having a projection depending from each cross-bar of said F, and notches on at least two of the extremities of said F, said stacks being adapted for assembly with said F-shapes inverted with respect to each other, and their ends in contact, said projections cooperating to form a magnetic shunt for said core, the central cross-bars of said F-shapes engaging each other so that said assembled stacks may not be separated in one direction, and said notches engaging each other so that said assembled stacks may not be separated in a second direction.

JOHN M. WILSON. 

